I built a 10 foot box last year out of treated lumber and used 1/4" lexan as a top sheet. First of all the lexan was 200$ for a 4x8 sheet. So I figured must be the cats ass. Had to cut a 2ft section to make it 10 ft long. The finished product was quite nice at the time. However, this summer the top sheet warped like hell literally ripping the screws from the wood and or pulled screws through the top sheet ie ruined.

Any insight or suggestions by experienced builders? Is the warping inevitable? Better ways to secure? Intrinsic problems with lexan?

Your using lexan to build boxes? I almost can guarantee it was the lexan that warped.. Did you leave it outside? Was it left in the sun? Most plastic gets soft at 250 to 400 degrees but I could understand it warping over a long period of time.

Your using lexan to build boxes? I almost can guarantee it was the lexan that warped.. Did you leave it outside? Was it left in the sun? Most plastic gets soft at 250 to 400 degrees but I could understand it warping over a long period of time.

Yes, lexan used for the top sheet. Yes, it was left in the sun. Yes, it was left outside. However, I've read on multiple locations that lexan is an acceptable material second only to HDPE.